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Martins F, Machado AL, Ribeiro A, Oliveira SM, Carvalho J, Matthiesen R, Backman V, Velho S. KRAS silencing alters chromatin physical organization and transcriptional activity in colorectal cancer cells. Res Sq 2024:rs.3.rs-3752760. [PMID: 38410476 PMCID: PMC10896403 DOI: 10.21203/rs.3.rs-3752760/v2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Clinical data revealed that KRAS mutant tumors, while initially sensitive to treatment, rapidly bypass KRAS dependence to acquire a drug-tolerant phenotype. However, the mechanisms underlying the transition from a drug-sensitive to a drug-tolerant state still elude us. Here, we show that global chromatin reorganization is a recurrent and specific feature of KRAS-dependent cells that tolerated KRAS silencing. We show that KRAS-dependent cells undergo G0/G1 cell cycle arrest after KRAS silencing, presenting a transcriptomic signature of quiescence. Proteomic analysis showed upregulated chromatin-associated proteins and transcription-associated biological processes. Accordingly, these cells shifted euchromatin/heterochromatin states, gained topologically associating domains, and altered the nanoscale physical organization of chromatin, more precisely by downregulating chromatin packing domains, a feature associated with the induction of quiescence. In addition, they also accumulated transcriptional alterations over time leading to a diversification of biological processes, linking chromatin alterations to transcriptional performance. Overall, our observations pinpoint a novel molecular mechanism of tolerance to KRAS oncogenic loss driven not by specific gene alterations but by global reorganization of genomic information, in which cells transition chromatin domain structure towards a more quiescent state and gain transcriptional reprogramming capacity.
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Affiliation(s)
| | | | | | | | | | | | | | - Sérgia Velho
- i3S - Institute for Research and Innovation in Health
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2
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Dias Carvalho P, Martins F, Mendonça S, Ribeiro A, Machado AL, Carvalho J, Oliveira MJ, Velho S. Mutant KRAS modulates colorectal cancer cells invasive response to fibroblast‐secreted factors through the HGF/C‐MET axis. Int J Cancer 2022; 151:1810-1823. [DOI: 10.1002/ijc.34225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 07/07/2022] [Accepted: 07/19/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Patrícia Dias Carvalho
- i3S ‐ Instituto de Investigação e Inovação em Saúde, Universidade do Porto Portugal
- IPATIMUP – Instituto de Patologia e Imunologia Molecular da Universidade do Porto Porto Portugal
- ICBAS ‐ Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto Porto Portugal
| | - Flávia Martins
- i3S ‐ Instituto de Investigação e Inovação em Saúde, Universidade do Porto Portugal
- IPATIMUP – Instituto de Patologia e Imunologia Molecular da Universidade do Porto Porto Portugal
- Department of Pathology FMUP – Faculty of Medicine of the University of Porto Porto Portugal
| | - Susana Mendonça
- i3S ‐ Instituto de Investigação e Inovação em Saúde, Universidade do Porto Portugal
- IPATIMUP – Instituto de Patologia e Imunologia Molecular da Universidade do Porto Porto Portugal
- Department of Pathology FMUP – Faculty of Medicine of the University of Porto Porto Portugal
| | - Andreia Ribeiro
- i3S ‐ Instituto de Investigação e Inovação em Saúde, Universidade do Porto Portugal
- IPATIMUP – Instituto de Patologia e Imunologia Molecular da Universidade do Porto Porto Portugal
| | - Ana Luísa Machado
- i3S ‐ Instituto de Investigação e Inovação em Saúde, Universidade do Porto Portugal
- IPATIMUP – Instituto de Patologia e Imunologia Molecular da Universidade do Porto Porto Portugal
- Department of Pathology FMUP – Faculty of Medicine of the University of Porto Porto Portugal
- Ciências Químicas e das Biomoléculas, Centro de Investigação em Saúde e Ambiente, Escola Superior de Saúde do Porto, Instituto Politécnico do Porto Porto Portugal
| | - Joana Carvalho
- i3S ‐ Instituto de Investigação e Inovação em Saúde, Universidade do Porto Portugal
- IPATIMUP – Instituto de Patologia e Imunologia Molecular da Universidade do Porto Porto Portugal
| | - Maria José Oliveira
- i3S ‐ Instituto de Investigação e Inovação em Saúde, Universidade do Porto Portugal
- INEB – Institute of Biomedical Engineering, University of Porto Porto Portugal
| | - Sérgia Velho
- i3S ‐ Instituto de Investigação e Inovação em Saúde, Universidade do Porto Portugal
- IPATIMUP – Instituto de Patologia e Imunologia Molecular da Universidade do Porto Porto Portugal
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3
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Barreto A, Santos J, Capitão A, Eusébio R, Pinheiro Damasceno É, Luísa Machado A, Rocha LS, Calisto V, Amorim MJB, Maria VL. Assessment of diphenhydramine toxicity - Is its mode of action conserved between human and zebrafish? Environ Int 2022; 164:107263. [PMID: 35504231 DOI: 10.1016/j.envint.2022.107263] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/11/2022] [Accepted: 04/20/2022] [Indexed: 06/14/2023]
Abstract
The main aim of the study is to evaluate the effects of the pharmaceutical diphenhydramine (DPH) on embryo-larvae Danio rerio across distinct levels of organization - individual and subcellular - and correlate those effects with the DPH mode of action (MoA) assessed by in silico analysis. An embryos heartbeat rate reduction was observed at 10 mg/L DPH, but 0.001 to 10 mg/L did not significantly affect the zebrafish survival, hatching and morphology. Larvae swimming distance decreased (hypoactivity) at 1 and 10 mg/L DPH. Moreover, the straightforward movements decrease and the increase in the zigzag movements or movements with direction changes, shown an erratic swimming behavior. Energy budgets decreased for lipid (0.01 mg/L DPH) and carbohydrate (10 mg/L DPH) contents. Cholinesterase (neural function) and glutathione S-transferase (Phase II biotransformation/antioxidant processes) increased their activities at 10 mg/L DPH, where a decrease in the total glutathione content (antioxidant system) was observed. DNA damage was found at 0.01 and 10 mg/L DPH. However, a DNA repair occurred after subsequent 72 h in clean media. The in silico study revealed a relevant conservation between human and zebrafish DPH target molecules. These data provide a valuable ecotoxicological information about the DPH effects and MoA to non-target organisms.
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Affiliation(s)
- Angela Barreto
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Joana Santos
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Ana Capitão
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Rodrigo Eusébio
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | | | - Ana Luísa Machado
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Luciana S Rocha
- Department of Chemistry & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Vânia Calisto
- Department of Chemistry & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Mónica J B Amorim
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Vera L Maria
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
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Silva CJM, Machado AL, Campos D, Rodrigues ACM, Patrício Silva AL, Soares AMVM, Pestana JLT. Microplastics in freshwater sediments: Effects on benthic invertebrate communities and ecosystem functioning assessed in artificial streams. Sci Total Environ 2022; 804:150118. [PMID: 34798725 DOI: 10.1016/j.scitotenv.2021.150118] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/13/2021] [Accepted: 08/31/2021] [Indexed: 05/22/2023]
Abstract
The high levels of microplastics (MPs) found in freshwaters, particularly in riverine sediments, may impose a threat to the macroinvertebrate communities with possible consequences at ecosystem-level. The present study aimed to assess the effects of a mixture of different sizes of polyethylene microplastics (PE-MPs) on the composition and structure of macroinvertebrate communities and key-functions, such as primary production and leaf litter decomposition. MPs were mixed in the sediment at three different concentrations (0.1, 1, and 10 g kg-1) already found in freshwater sediments to enhance the relevance of the work. After eight days of exposure to PE-MPs, the observed changes in macroinvertebrate community structure were mostly due to the reduction in the abundance of deposit-feeders and grazers that were reduced by ca 31-50% and 34-39%, in the two highest MPs concentrations respectively, in comparison with the control treatment after 8 days of exposure. MPs internal concentrations were detected only in organisms exposed to plastic particles within artificial streams with chironomids and mayflies presenting higher MPs internal levels (average of 115 particles/individual found in chironomids, 166/individual for Baetis sp. and 415 particles/individual for Ephemerella sp.) suggesting higher ingestion of plastic microparticles. Nevertheless, the alterations in the community structure did not translate into impairments in the functional endpoints analysed, leaf litter decomposition and primary production, that were expected due to possible sub-lethal effects (e.g., feeding inhibition) on detritivores and grazers. This study represents one of the few assessments of MPs effects on freshwater benthic macroinvertebrate community structure and the first that simultaneously considered ecosystem-level functional endpoints. Further research combining different microplastics and longer exposure periods are needed to raise knowledge on potential ecological consequences of MPs to freshwaters.
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Affiliation(s)
- Carlos J M Silva
- CESAM - Centre for Environmental and Marine Studies & Department of Biology, University of Aveiro, Portugal
| | - Ana Luísa Machado
- CESAM - Centre for Environmental and Marine Studies & Department of Biology, University of Aveiro, Portugal.
| | - Diana Campos
- CESAM - Centre for Environmental and Marine Studies & Department of Biology, University of Aveiro, Portugal
| | - Andreia C M Rodrigues
- CESAM - Centre for Environmental and Marine Studies & Department of Biology, University of Aveiro, Portugal
| | - Ana L Patrício Silva
- CESAM - Centre for Environmental and Marine Studies & Department of Biology, University of Aveiro, Portugal
| | - Amadeu M V M Soares
- CESAM - Centre for Environmental and Marine Studies & Department of Biology, University of Aveiro, Portugal
| | - João L T Pestana
- CESAM - Centre for Environmental and Marine Studies & Department of Biology, University of Aveiro, Portugal
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Simão FCP, Gravato C, Machado AL, Soares AMVM, Pestana JLT. Effects of pyrene and benzo[a]pyrene on the reproduction and newborn morphology and behavior of the freshwater planarian Girardia tigrina. Chemosphere 2021; 264:128448. [PMID: 33032223 DOI: 10.1016/j.chemosphere.2020.128448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 09/22/2020] [Accepted: 09/24/2020] [Indexed: 06/11/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants of aquatic ecosystems. Because they are persistent, there is great potential for chronic toxicity to aquatic species, and the evaluation of reproductive effects is fundamental. In this context, planarians are interesting experimental animals, since they can be sensitive to environmental pollutants, and a wide range of reproductive-related endpoints can be assessed. In this work we evaluated fecundity (number of cocoons), fertility (number of newborns), newborn anomalies, adult weight, regenerative abilities and PAH-residues in tissues of the freshwater planarian Girardia tigrina, exposed to either pyrene or benzo[a]pyrene (B[a]P). Pyrene reduced planarian fecundity and fertility at 18.75 μg L-1 and 75.00 μg L-1, while B[a]P reduced planarian fecundity at the 37.50 μg L-1 treatment, which was accompanied by a 33.7% reduction in fertility. Cocoons were kept in clean media and newborns were evaluated for behavioral and morphological anomalies. Many of the newborns resulting from the B[a]P experiment revealed behavioral anomalies, such as spasms and uncoordinated movements. These behavioral anomalies were observed in 12.9% and 38.2% of newborns resulting from the exposure of adult planarians to 9.38 μg L-1 and 37.50 μg L-1 of B[a]P, respectively. This study is the first report on the effects of PAHs in freshwater planarians' sexual reproduction and a decreased reproductive output was evidenced. Moreover, the exposure of adults to B[a]P lead to defects in newborns, raising concern on the possible long-term consequences of these compounds for natural planarian populations.
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Affiliation(s)
- Fátima C P Simão
- CESAM & Departamento de Biologia, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
| | - Carlos Gravato
- Faculdade de Ciências & CESAM, Universidade de Lisboa, Campo Grande, 1749-016, Lisboa, Portugal
| | - Ana Luísa Machado
- CESAM & Departamento de Biologia, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Amadeu M V M Soares
- CESAM & Departamento de Biologia, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - João L T Pestana
- CESAM & Departamento de Biologia, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
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6
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Simão FCP, Gravato C, Machado AL, Soares AMVM, Pestana JLT. Toxicity of different polycyclic aromatic hydrocarbons (PAHs) to the freshwater planarian Girardia tigrina. Environ Pollut 2020; 266:115185. [PMID: 32777698 DOI: 10.1016/j.envpol.2020.115185] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 06/18/2020] [Accepted: 07/03/2020] [Indexed: 06/11/2023]
Abstract
Freshwater planarians have been gaining relevance as experimental animals for numerous research areas given their interesting features, such as high regeneration potential, shared features with the vertebrates' nervous system or the range of endpoints that can be easily evaluated in response to contaminants. Ecotoxicological research using these animals has been steadily increasing in the past decades, as planarians' potentialities for this research area are being recognized. In this work, we used polycyclic aromatic hydrocarbons (PAHs) as model contaminants and evaluated effects of exposure to phenanthrene, pyrene and benzo[a]pyrene (B[a]P) in planarians. The freshwater planarian Girardia tigrina was chosen and mortality, cephalic regeneration (during and post-exposure), behavioral endpoints and presence of PAHs in tissues, were evaluated. Mortality was only observed in planarians exposed to phenanthrene, with an estimated LC50 of 830 μg L-1. Results indicate that planarian behavioral endpoints were very sensitive in response to sub-lethal concentrations of PAHs, showing a greater sensitivity towards B[a]P and pyrene. Briefly, post-exposure locomotion and post-exposure feeding were significantly impaired by sub-lethal concentrations of all compounds, whereas regeneration of photoreceptors was only significantly delayed in planarians exposed to pyrene. Moreover, levels of PAH-type compounds in planarian tissues followed a concentration-dependent increase, showing uptake of compounds from experimental solutions. The present results highlight the importance of studying alternative and complementary endpoints, such as behavior, not only because these may be able to detect effects at lower levels of contamination, but also due to their ecological relevance. The simplicity of evaluating a wide range of responses to contaminants further demonstrates the utility of freshwater planarians for ecotoxicological research.
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Affiliation(s)
- Fátima C P Simão
- CESAM & Departamento de Biologia, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
| | - Carlos Gravato
- Faculdade de Ciências & CESAM, Universidade de Lisboa, 1749-016, Campo Grande, Lisboa, Portugal
| | - Ana Luísa Machado
- CESAM & Departamento de Biologia, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Amadeu M V M Soares
- CESAM & Departamento de Biologia, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - João L T Pestana
- CESAM & Departamento de Biologia, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
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Soares MP, Machado AL, Hayd L, Soares A, Domingues I. Effects of pH and nitrites on the toxicity of a cypermethrin-based pesticide to zebrafish embryos. Environ Toxicol Pharmacol 2020; 76:103351. [PMID: 32062415 DOI: 10.1016/j.etap.2020.103351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 01/31/2020] [Accepted: 02/03/2020] [Indexed: 06/10/2023]
Abstract
Physical and chemical water parameters have an important role on the toxicity of environmental contaminants by affecting their degradation, transformation and bioavailability. The objective of this study was to evaluate the effects of pH and nitrite variation on the toxicity of the cypermethrin based pesticide Barrage®. Zebrafish embryos (Danio rerio) were exposed to a combination of pH or nitrite and cypermethrin through the Barrage® formulation for 96 h and lethal and developmental endpoints assessed. Concerning mortality, pH seemed to increase Barrage® toxicity, while nitrite concentrations tested did not seem to change Barrage® lethality. At sublethal level, either for combinations involving pH or nitrites, results suggested some interactive effects of environmental and chemical factors, highlighting the need of further research. This work suggests that sublethal endpoints should be included in the assessment of combined effects of compounds given that they can provide important information not obtained through lethality.
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Affiliation(s)
- Mayara Pereira Soares
- State University of Mato Grosso do Sul (UEMS), Animal Science Graduate Program, Aquidauana-UEMS Km 12, 79200-000, Aquidauana, MS, Brazil
| | - Ana Luísa Machado
- Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Liliam Hayd
- State University of Mato Grosso do Sul (UEMS), Animal Science Graduate Program, Aquidauana-UEMS Km 12, 79200-000, Aquidauana, MS, Brazil
| | - Amadeu Soares
- Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Inês Domingues
- Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
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Correia D, Almeida AR, Santos J, Machado AL, Koba Ucun O, Žlábek V, Oliveira M, Domingues I. Behavioral effects in adult zebrafish after developmental exposure to carbaryl. Chemosphere 2019; 235:1022-1029. [PMID: 31561291 DOI: 10.1016/j.chemosphere.2019.07.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 06/10/2023]
Abstract
Chemical exposure during the early life stages of development may have long lasting effects on organisms that are rarely studied. The present work intended to evaluate the effect of embryonic exposure to the pesticide carbaryl on adult fish behavior. Zebrafish (Danio rerio) embryos were exposed, for 4 days, to sublethal concentrations of carbaryl (0.01, 0.1 and 1.0 mg/L) plus a control and then kept in standard cultivation conditions until adulthood. A battery of behavioral tests was then performed to assess anxiety-like behavior (locomotor activity, thigmotaxis and novel tank diving test), social behavior, and feeding. Developmental exposure of zebrafish to sublethal concentrations of carbaryl produced important behavioral alterations in the adulthood. Main effects included decreased locomotion/hypoactivity (increase in slow movements and decrease of medium and rapid movements), especially in the light periods. Moreover, spatial pattern also changed: while during dark periods control fish increased activity in the outer zone of the tank, this was not observed in exposed fish. Overall, this demonstrated the importance of life stage exposure, clearly demonstrating long lasting effects of a (chemical) stress event at embryonic stages. This data supports the need of considering this scenario in environmental risk evaluations. Further work should focus on the mechanistic effects of developmental disruption responsible for the effects observed.
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Affiliation(s)
- Daniela Correia
- Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Ana Rita Almeida
- Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Joana Santos
- Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Ana Luísa Machado
- Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Olga Koba Ucun
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zatisi 728/II, Vodnany, 389 25, Czech Republic
| | - Vladimír Žlábek
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zatisi 728/II, Vodnany, 389 25, Czech Republic
| | - Miguel Oliveira
- Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
| | - Inês Domingues
- Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
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Almeida AR, Tacão M, Machado AL, Golovko O, Zlabek V, Domingues I, Henriques I. Long-term effects of oxytetracycline exposure in zebrafish: A multi-level perspective. Chemosphere 2019; 222:333-344. [PMID: 30708167 DOI: 10.1016/j.chemosphere.2019.01.147] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/23/2019] [Accepted: 01/25/2019] [Indexed: 05/07/2023]
Abstract
Oxytetracycline (OTC) is a broad-spectrum antibiotic widely used in livestock production. Like many other pharmaceuticals, OTC is not completely metabolized by the organism and thus, increasing amounts of the compound are being detected in the aquatic environment. The assessment of the environmental risk of pharmaceuticals is hindered by their very low concentrations and specific modes of action and thus relevant exposure scenarios and sensitive endpoints are needed. Thus, this work aimed to study the long-term effect of OTC exposure in zebrafish (at behavior and biochemical levels) and associated bacterial communities (fish gut and water bacterial communities). Results revealed that at behavioral level, boldness increase (manifested by increased exploratory behavior of a new environment) was observed in fish exposed to low OTC concentrations. Moreover, changes in fish swimming pattern were observed in light periods (increased stress response: hyperactivity and freezing) probably due to photo-sensibility conferred by OTC exposure. Effects at biochemical level suggest that long-term exposure to OTC interfere with cellular energy allocation mainly by reducing lipids levels and increasing energy consumption. Moreover, evidences of oxidative damage were also observed (reduced levels of TG, GST and CAT). The analysis of water and gut microbiome revealed changes in the structure and diversity of bacterial communities potentially leading to changes in communities' biological function. Some of the effects were observed at the lowest concentration tested, 0.1 μg/L which is a concentration already detected in the environment and thus clearly demonstrating the need of a serious ecotoxicological assessment of OTC effects on non-target organisms.
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Affiliation(s)
- Ana Rita Almeida
- Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Marta Tacão
- Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Ana Luísa Machado
- Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Oksana Golovko
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zatisi 728/II, Vodnany 389 25, Czech Republic
| | - Vladimir Zlabek
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zatisi 728/II, Vodnany 389 25, Czech Republic
| | - Inês Domingues
- Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
| | - Isabel Henriques
- CESAM & Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Calçada Martins de Freitas, 3000-456 Coimbra, Portugal
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Viana PS, Orlandi MO, Pavarina AC, Machado AL, Vergani CE. Chemical composition and morphology study of bovine enamel submitted to different sterilization methods. Clin Oral Investig 2017; 22:733-744. [PMID: 28667399 DOI: 10.1007/s00784-017-2148-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/02/2017] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The morphology and chemical composition of enamel submitted to different sterilization methods was studied. METHODS X-ray photoelectron spectroscopy (XPS), field emission gun scanning electron microscopy (FEG-SEM), and energy-dispersive X-ray spectroscopy (EDS) were performed to evaluate 50 bovine enamel specimens sterilized using four methods: microwaving (MI), gamma irradiation (GI), ethylene oxide (EO), and steam autoclave (SA). Non-sterilized specimens were used as control. RESULTS XPS indicated that the concentration of P (phosphorus), CO3 (carbonate), and CO3/P was not changed in all groups. GI produced no significant change on elemental composition. SA produced the major decrease in calcium (Ca), Ca/P ratio, and increase in N (nitrogen). MI was found to decrease Ca, Ca/P ratio and O (oxygen), and increase in C (carbon) and N. EO produced decrease in Ca and O with increased C concentration. FEG-SEM revealed surface and in-depth morphological changes on SA specimens. Minor surface alterations were observed for EO and for MI groups, and no alteration was observed on GI group. EDS indicated no difference on elemental composition of enamel bulk among groups. CONCLUSIONS SA produced mineral loss and morphological alterations on surface and in depth. MI and EO sterilization caused mineral loss showing only slight alteration on enamel surface. GI sterilization preserves the morphological characteristics of enamel. The sterilization methods could be classified from lower to high damage as GI < MI < EO < SA. CLINICAL RELEVANCE This is a comprehensive comparative study where different methods for enamel sterilization were investigated in terms of chemical changes. The results presented here may help researchers to choose the most appropriate method for their research setting and purpose.
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Affiliation(s)
- P S Viana
- Department of Dental Materials and Prosthodontics, Araraquara Dental School, Faculdade de Odontologia de Araraquara, UNESP, Univ Estadual Paulista, Rua Humaitá, N° 1680, Araraquara, SP, CEP:14801-903, Brazil
- Faculdade de Odontologia, Universidade Santo Amaro, UNISA, São Paulo, Brazil
| | - M O Orlandi
- Department of Physical Chemistry, Institute of Chemistry, UNESP, Univ Estadual Paulista, Araraquara, Brazil
| | - A C Pavarina
- Department of Dental Materials and Prosthodontics, Araraquara Dental School, Faculdade de Odontologia de Araraquara, UNESP, Univ Estadual Paulista, Rua Humaitá, N° 1680, Araraquara, SP, CEP:14801-903, Brazil
| | - A L Machado
- Department of Dental Materials and Prosthodontics, Araraquara Dental School, Faculdade de Odontologia de Araraquara, UNESP, Univ Estadual Paulista, Rua Humaitá, N° 1680, Araraquara, SP, CEP:14801-903, Brazil
| | - C E Vergani
- Department of Dental Materials and Prosthodontics, Araraquara Dental School, Faculdade de Odontologia de Araraquara, UNESP, Univ Estadual Paulista, Rua Humaitá, N° 1680, Araraquara, SP, CEP:14801-903, Brazil.
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Alves AC, Monteiro MS, Machado AL, Oliveira M, Bóia A, Correia A, Oliveira N, Soares AMVM, Loureiro S. Mercury levels in parturient and newborns from Aveiro region, Portugal. J Toxicol Environ Health A 2017; 80:697-709. [PMID: 28524771 DOI: 10.1080/15287394.2017.1286926] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Since the outbreak of methylmercury (MeHg) poisoning in Japan and Iraq, mercury (Hg) is classified as well-established teratogen. The Portuguese region of Aveiro faced some decades ago an environmental Hg contamination due to activities from a chlor-alkali plant. Until now, no apparent evaluation was conducted regarding prenatal exposure to Hg in this area. The main objectives of this study were to: i) assess maternal and fetal exposure to Hg in the Aveiro region using noninvasive biological matrices; ii) examine the influence of variables that may contribute to Hg exposure during pregnancy; and iii) improve knowledge regarding metal accumulation and distribution over the maternal-fetal-placental unit. This study was performed in 50 mother-newborn pairs from the Aveiro district. Total Hg (THg) was quantified in maternal scalp hair, placenta, amniotic membrane, and umbilical cord. Maternal hair presented THg levels with a mean value of 900 ng/g, which is lower than the USEPA and WHO acceptable threshold. Regarding THg levels in placenta and umbilical cord, mean values were similar (decidua basalis: 32.84 ng/g; chorionic plate: 30.18 ng/g; umbilical cord: 30.67 ng/g). The amniotic membrane presented the highest THg levels with a mean concentration of 42.35 ng/g, reaching a maximum of 134.1 ng/g. Further, a significant positive correlation was noted between THg levels found in hair, and all matrices analyzed reinforcing the use of hair in biomonitoring studies with respect to maternal exposure to Hg. In general, levels of THg found in our study were lower than those in previous studies performed in Europe. Consumption of fish rich in selenium and bottled water was negatively correlated with THg levels. Finally, data demonstrated that Hg is capable of crossing the placental barrier and accumulate in placental tissues. Amniotic membrane seemed to play a role in metal detoxification, but further investigations are necessary to examine whether this catabolic process affects Hg accumulation.
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Affiliation(s)
- Ana Catarina Alves
- a Department of Biology & Centro de Estudos do Ambiente e do MAR (CESAM) , University of Aveiro , Aveiro , Portugal
| | - Marta S Monteiro
- a Department of Biology & Centro de Estudos do Ambiente e do MAR (CESAM) , University of Aveiro , Aveiro , Portugal
| | - Ana Luísa Machado
- a Department of Biology & Centro de Estudos do Ambiente e do MAR (CESAM) , University of Aveiro , Aveiro , Portugal
| | - Mário Oliveira
- b Obstetrics and Gynecology Department, Infante D.Pedro Hospital , Centro Hospitalar Baixo , Vouga , EPE, Aveiro , Portugal
| | - Ana Bóia
- b Obstetrics and Gynecology Department, Infante D.Pedro Hospital , Centro Hospitalar Baixo , Vouga , EPE, Aveiro , Portugal
| | - Ana Correia
- b Obstetrics and Gynecology Department, Infante D.Pedro Hospital , Centro Hospitalar Baixo , Vouga , EPE, Aveiro , Portugal
| | - Nuno Oliveira
- b Obstetrics and Gynecology Department, Infante D.Pedro Hospital , Centro Hospitalar Baixo , Vouga , EPE, Aveiro , Portugal
| | - Amadeu M V M Soares
- a Department of Biology & Centro de Estudos do Ambiente e do MAR (CESAM) , University of Aveiro , Aveiro , Portugal
| | - Susana Loureiro
- a Department of Biology & Centro de Estudos do Ambiente e do MAR (CESAM) , University of Aveiro , Aveiro , Portugal
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Andrade TS, Henriques JF, Almeida AR, Machado AL, Koba O, Giang PT, Soares AMVM, Domingues I. Corrigendum to "Carbendazim exposure induces developmental, biochemical and behavioural disturbance in zebrafish embryos" [Aquat. Toxicol. 170 (2016) 390-399]. Aquat Toxicol 2016; 173:228. [PMID: 29622183 DOI: 10.1016/j.aquatox.2016.01.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Affiliation(s)
- Thayres S Andrade
- Dept. of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
| | - Jorge F Henriques
- Dept. of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Ana Rita Almeida
- Dept. of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Ana Luísa Machado
- Dept. of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Olga Koba
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zatisi 728/II, Vodnany 389 25, Czech Republic
| | - Pham Thai Giang
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zatisi 728/II, Vodnany 389 25, Czech Republic
| | - Amadeu M V M Soares
- Dept. of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Inês Domingues
- Dept. of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
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Andrade TS, Henriques JF, Almeida AR, Machado AL, Koba O, Giang PT, Soares AMVM, Domingues I. Carbendazim exposure induces developmental, biochemical and behavioural disturbance in zebrafish embryos. Aquat Toxicol 2016; 170:390-399. [PMID: 26653011 DOI: 10.1016/j.aquatox.2015.11.017] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 11/11/2015] [Accepted: 11/18/2015] [Indexed: 06/05/2023]
Abstract
Carbendazim is a widely used broad spectrum benzimidazole fungicide; however, its effects to non-target aquatic organisms are poorly studied. The aim of this study was to investigate the toxic effects of carbendazim to zebrafish early life stages at several levels of biological organization, including developmental, biochemical and behavioural levels. The embryo assay was done following the OECD guideline 236 and using a concentration range between 1.1 and 1.8mg/L. Lethal and developmental endpoints such as hatching, edemas, malformations, heart beat rate, body growth and delays were assessed in a 96h exposure. A sub-teratogenic range (from 0.16 to 500μg/L) was then used to assess effects at biochemical and behavioural levels. Biochemical markers included cholinesterase (ChE), glutathione-S-transferase (GST), lactate dehydrogenase (LDH) and catalase (CAT) and were assessed at 96h. The locomotor behaviour was assessed using an automated video tracking system at 120h. Carbendazim (96h-LC50 of 1.75mg/L) elicited several developmental anomalies in zebrafish embryos with EC50 values ranging from 0.85 to 1.6mg/L. ChE, GST and LDH activities were increased at concentrations equal or above 4μg/L. The locomotor assay showed to be extremely sensitive, detecting effects in time that larvae spent swimming at concentrations of 0.16μg/L and thus, being several orders of magnitude more sensitive that developmental parameters or lethality. These are ecological relevant concentrations and highlight the potential of behavioural endpoints as early warning signs for environmental stress. Further studies should focus on understanding how the behavioural disturbances measured in these types of studies translate into fitness impairment at the adult stage.
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Affiliation(s)
- Thayres S Andrade
- Dept. of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
| | - Jorge F Henriques
- Dept. of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Ana Rita Almeida
- Dept. of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Ana Luísa Machado
- Dept. of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Olga Koba
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zatisi 728/II, Vodnany 389 25, Czech Republic
| | - Pham Thai Giang
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zatisi 728/II, Vodnany 389 25, Czech Republic
| | - Amadeu M V M Soares
- Dept. of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Inês Domingues
- Dept. of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
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Machado AL, Brito JC, Medeiros V, Leitão M, Moutinho C, Jesus A, Ferrand Y, Gonçalves D. Distribution and habitat preferences of Eurasian woodcock Scolopax rusticola in S. Miguel island (Azores) during the breeding season. Wildlife Biology 2008. [DOI: 10.2981/0909-6396(2008)14[129:dahpoe]2.0.co;2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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15
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Jorge JH, Giampaolo ET, Vergani CE, Machado AL, Pavarina AC, Cardoso de Oliveira MR. Clinical evaluation of abutment teeth of removable partial denture by means of the Periotest method. J Oral Rehabil 2007; 34:222-7. [PMID: 17302951 DOI: 10.1111/j.1365-2842.2006.01644.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Prosthodontics should be one of the means of establishing conditions for the maintenance of periodontal health. The forces applied to the abutment teeth and their effects are very important considerations in the design and construction of the removable partial dentures. This 6-month follow-up clinical study evaluated the degree of mobility of abutment teeth of distal extension and tooth supported removable partial dentures by using Periotest. Two types of clasp design were selected for evaluation. In cases with unilateral and bilateral distal-extension, a clasp design including a T clasp of Roach retentive arm, a rigid reciprocal arm and a mesial rest were used. For the abutments of tooth-supported removable partial dentures, a second clasp design with a cast circumferential buccal retentive arm, a rigid reciprocal clasp arm and a rest adjacent to the edentulous ridges was selected. A total of 68 abutment teeth was analysed. Periotest values were made at the time of denture placement (control) and at 1, 3 and 6 months after the denture placement. The statistical analysis was performed using Friedman test. All analysis was performed at a 0.05 level of significance. The results revelled that no significant changes in tooth mobility were observed during the 6-months follow-up (P > 0.05). In conclusion, our findings suggest that adequate oral hygiene instructions, careful prosthetic treatment planning and regular recall appointments play an important role in preventing changes in abutment tooth mobility caused by removable partial denture placement.
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Affiliation(s)
- J H Jorge
- Department of Dental Materials and Prosthodontics, São Paulo State University, Araraquara Dental School, São Paulo, Brazil
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16
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Urban VM, Cass QB, Oliveira RV, Giampaolo ET, Machado AL. Development and application of methods for determination of residual monomer in dental acrylic resins using high performance liquid chromatography. Biomed Chromatogr 2006; 20:369-76. [PMID: 16177959 DOI: 10.1002/bmc.575] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Two high-performance liquid chromatographic methods for determination of residual monomer in dental acrylic resins are described. Monomers were detected by their UV absorbance at 230 nm, on a Nucleosil C18 (5 microm particle size, 100 A pore size, 15 x 0.46 cm i.d.) column. The separation was performed using acetonitrile-water (55:45 v/v) containing 0.01% triethylamine (TEA) for methyl methacrylate and butyl methacrylate, and acetonitrile-water (60:40 v/v) containing 0.01% TEA for isobutyl methacrylate and 1,6-hexanediol dimethacrylate as mobile phases, at a flow rate of 0.8 mL/min. Good linear relationships were obtained in the concentration range 5.0-80.0 microg/mL for methyl methacrylate, 10.0-160.0 microg/mL for butyl methacrylate, 50.0-500.0 microg/mL for isobutyl methacrylate and 2.5-180.0 microg/mL for 1,6-hexanediol dimethacrylate. Adequate assay for intra- and inter-day precision and accuracy was observed during the validation process. An extraction procedure to remove residual monomer from the acrylic resins was also established. Residual monomer was obtained from broken specimens of acrylic disks using methanol as extraction solvent for 2 h in an ice-bath. The developed methods and the extraction procedure were applied to dental acrylic resins, tested with or without post-polymerization treatments, and proved to be accurate and precise for the determination of residual monomer content of the materials evaluated.
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Affiliation(s)
- V M Urban
- Department of Dental Materials and Prosthodontics, São Paulo State University, UNESP, Araraquara, São Paulo, Brazil
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17
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Abstract
The disinfection of dental prostheses by immersion in a chemical solution should be capable of rapid inactivation of pathogenic microorganisms, without causing any adverse effect on the denture base resins. This study evaluated the effect of disinfection immersion on the transverse strength of two heat-cured resins. The denture base resins (Lucitone 550 and QC 20) were polymerized according to the manufacturers' instructions. After polymerization, the specimens were polished, and then stored in water at 37 degrees C for 50 +/- 2 h prior immersion in one of the following solutions for 10 min: 4% chlorhexidine, 1% sodium hypochlorite and 3.78% sodium perborate. The specimens were submitted to disinfection twice, simulating when dentures come from the patient and before being returned to the patient. Ten specimens were made for each group. The transverse strength was evaluated by a 3-point bend test. The flexural strength of the two denture base acrylic resins evaluated remained unaffected after immersion in the three solutions evaluated. In general, the QC 20 resin specimens exhibited lower transverse strength than the Lucitone 550 resin specimens, regardless of immersion solutions.
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Affiliation(s)
- A C Pavarina
- Department of Removable Prosthodontics, São Paulo State University (UNESP), Araraquara Dental School, Araraquara, SP, Brazil.
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Abstract
This investigation studied the effects of disinfectant solutions on the hardness of acrylic resin denture teeth. The occlusal surfaces of 64 resin denture teeth were ground flat with abrasives up to 400-grit silicon carbide paper. Measurements were made after polishing and after the specimens were stored in water at 37 degrees C for 48 h. The specimens were then divided into four groups and immersed in chemical disinfectants (4% chlorhexidine; 1% sodium hypochlorite and sodium perborate) for 10 min. The disinfection methods were performed twice to simulate clinical conditions and hardness measurements were made. Specimens tested as controls were immersed in water during the same disinfection time. Eight specimens were produced for each group. After desinfection procedures, testing of hardness was also performed after the samples were stored at 37 degrees C for 7, 30, 60, 90 and 120 days. Data were analysed using two-way analysis of variance (anova) and Tukey's test at 95% confidence level. According to the results, no significant differences were found between materials and immersion solutions (P > 0.05). However, a continuous decrease in hardness was noticed after ageing (P < 0.05). It was conclude that the surfaces of both acrylic resin denture teeth softened upon immersion in water regardless the disinfecting solution.
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Affiliation(s)
- A C Pavarina
- Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), Araraquara Dental School, Araraquara, SP, Brazil.
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Pavarina AC, Pizzolitto AC, Machado AL, Vergani CE, Giampaolo ET. An infection control protocol: effectiveness of immersion solutions to reduce the microbial growth on dental prostheses. J Oral Rehabil 2003; 30:532-6. [PMID: 12752936 DOI: 10.1046/j.1365-2842.2003.01093.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This investigation evaluated the effectiveness of an infection control protocol for cleansing and disinfecting removable dental prostheses. Sixty-four dentures were rubbed with sterile cotton swab immediately after they had been taken from patients' mouths. Samples were individually placed in the culture medium and immediately incubated at 37 +/- 2 degrees C. The dentures were scrubbed for 1 min with 4% chlorhexidine, rinsed for 1 min in sterile water and placed for 10 min in one of the following immersion solutions: 4% chlorhexidine gluconate, 1% sodium hypochlorite, Biocide (iodophors) and Amosan (alkaline peroxide). After the disinfection procedures, the dentures were immersed in sterile water for 3 min, reswabbed and the samples were incubated. All samples obtained in the initial culture were contaminated with micro-organisms. All the lower dentures immersed in Biocide showed positive growth, and the upper dentures were positive for growth in six of eight dentures. The 4% chlorhexidine gluconate, 1% sodium hypochlorite and Amosan solutions have been proved effective to reduce the growth of the micro-organisms in the 10 min immersion period. The protocol evaluated in this study seems to be a viable method to prevent cross-contamination between dental personnel and patients.
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Affiliation(s)
- A C Pavarina
- Department of Removable Prosthodontics, São Paulo State University (UNESP), Araraquara Dental School, Araraquara, SP, Brazil.
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20
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Leles CR, Machado AL, Vergani CE, Giampaolo ET, Pavarina AC. Bonding strength between a hard chairside reline resin and a denture base material as influenced by surface treatment. J Oral Rehabil 2001; 28:1153-7. [PMID: 11874516 DOI: 10.1046/j.1365-2842.2001.00786.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Direct relining of dentures made with hard chairside reline resins is faster than laboratory-processed reline systems and the patient is not without the prosthesis for the time necessary to perform the laboratory procedures. However, a weak bond between the autopolymerizing acrylic reline resins and the denture base material has been observed. This study evaluated the effect of six different surface treatments on the bond strength between a hard chairside reline acrylic resin and a heat-cured acrylic resin. Specimens of the heat-cured acrylic resin were divided into seven groups. One of these groups remained intact. In the other groups, a 10-mm square section was removed from the centre of each specimen. The bonding surfaces were then treated with (i) methyl methacrylate monomer, (ii) isobutyl methacrylate monomer, (iii) chloroform, (iv) acetone, (v) experimental adhesive and (vi) no surface treatment -- control group. Kooliner acrylic resin was packed into the square sections and polymerized. The bonding strength was evaluated by a three-point loading test. The results were submitted to one-way analysis of variance (ANOVA) followed by a Tukey multiple range test at a 5% level of significance. No significant difference was found between the surface treatment with Lucitone 550 monomer or chloroform, but both were stronger than the majority of the other groups. The bond strength provided by all the surface treatments was lower than that of the intact heat-cured resin.
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Affiliation(s)
- C R Leles
- Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), Araraquara Dental School, Araraquara, SP, Brazil
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Pavarina AC, Machado AL, Vergani CE, Giampaolo ET. Overlay removable partial dentures for a patient with ectodermal dysplasia: a clinical report. J Prosthet Dent 2001; 86:574-7. [PMID: 11753305 DOI: 10.1067/mpr.2001.119981] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The orofacial characteristics of ectodermal dysplasia include anodontia or hypodontia, hypoplastic conical teeth, underdevelopment of the alveolar ridges, frontal bossing, a depressed nasal bridge, protuberant lips, and hypotrichosis. Patients with this disease often need complex prosthetic treatment. The options for a definitive treatment plan may include fixed, removable, or implant-supported prostheses, singly or in combination. However, financial constraints and other priorities can prevent patients from choosing the most desirable treatment. This clinical report describes the diagnosis and treatment of ectodermal dysplasia in an 18-year-old man. The treatment included interim removable partial dentures fabricated to establish an acceptable therapeutic occlusal vertical dimension, followed by definitive overlay removable partial dentures and composite restorations.
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Affiliation(s)
- A C Pavarina
- Araraquara Dental School, São Paulo State University, Araraquara, Brazil.
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Vergani CE, Machado AL, Giampaolo ET, Pavarina AC. Effect of surface treatments on the bond strength between composite resin and acrylic resin denture teeth. INT J PROSTHODONT 2000; 13:383-6. [PMID: 11203658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
PURPOSE This investigation studied the effects of 3 surface treatments on the shear bond strength of a light-activated composite resin bonded to acrylic resin denture teeth. MATERIALS AND METHODS The occlusal surfaces of 30 acrylic resin denture teeth were ground flat with up to 400-grit silicon carbide paper. Three different surface treatments were evaluated: (1) the flat ground surfaces were primed with methyl methacrylate (MMA) monomer for 180 seconds; (2) light-cured adhesive resin was applied and light polymerized according to the manufacturer's instructions; and (3) treatment 1 followed by treatment 2. The composite resin was packed on the prepared surfaces using a split mold. The interface between tooth and composite was loaded at a cross-head speed of 0.5 mm/min until failure. RESULTS Analysis of variance indicated significant differences between the surface treatments. Results of mean comparisons using Tukey's test showed that significantly higher shear bond strengths were developed by bonding composite resin to the surfaces that were previously treated with MMA and then with the bonding agent when compared to the other treatments. CONCLUSION Combined surface treatment of MMA monomer followed by application of light-cured adhesive resin provided the highest shear bond strength between composite resin and acrylic resin denture teeth.
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Affiliation(s)
- C E Vergani
- São Paulo State University, Araraquara Dental School, São Paulo, Brazil.
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Machado AL, de Oliveira FB, da Silva WV, Hupsel ZN. [Social representations in nursing: commentaries on theses and dissertations]. Rev Esc Enferm USP 1997; 31:486-97. [PMID: 9582840 DOI: 10.1590/s0080-62341997000300010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The starting point of this work consists on a revision of thesis and dissertations developed by nurses aiming to check how the social representation was used as a theoretical referential on these researches. Through a systematic reading of these works some points were dettached, as thematic, main result as and reflections proposed in order to atain professional practice nursing. It was ascertained from the analysed work that this theoretical referential is used by nurses, and that some studies developed introduce significative results from these professionals.
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Affiliation(s)
- A L Machado
- Departamento de Enfermagem Materno-Infantil e Psiquiátrica da EEUSP
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Ribeiro-dos-Santos AK, Santos SE, Machado AL, Guapindaia V, Zago MA. Reply to Monsalve on "Mitochondrial DNA in ancient Ameridians," American Journal of Physical Anthropology (1997) 103:423-425. Am J Phys Anthropol 1997; 103:571. [PMID: 9292173 DOI: 10.1002/(sici)1096-8644(199708)103:4<571::aid-ajpa13>3.0.co;2-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Ribetio-dos-Santos AK, Santos SE, Machado AL, Guapindaia V, Zago MA. Heterogeneity of mitochondrial DNA haplotypes in Pre-Columbian Natives of the Amazon region. Am J Phys Anthropol 1996; 101:29-37. [PMID: 8876812 DOI: 10.1002/(sici)1096-8644(199609)101:1<29::aid-ajpa3>3.0.co;2-8] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We report the first study of mitochondrial DNA (mtDNA) sequencing from ancestral Amerindian populations of the South American continent. Sequencing of the D-loop region of mtDNA was carried out for bone fragments from 18 skeletons of Pre-Columbian Amerinidians. The skeletons were excavated in different archeological sites of the Brazilian Amazon region, with dating estimated at 500-4,000 years before the present. The sequencing of at least 354 bases permitted the identification of 13 haplotypes defined by variation of 26 nucleotide positions. Two haplotypes were shared by more than one sample, while 11 haplotypes were observed for a single sample. Seven haplotypes observed in 11 individuals (61% of the sample) belong to the four haplogroups described by Horai et al. (1993). Three samples that shared the transition C-->T in positions 16,223 and 16,278 formed a fifth haplogroup, which has been previously described in present-day Indian populations. Finally, four samples formed a heterogeneous group but each haplotype had at least one mutation typically detected in Asian or Mongoloid populations. Thus, although only haplotypes shared by Asian populations were detected, a wide haplotype variability was observed. If our sample is representative of Pre-Columbian South America, the percentage of haplotypes (39%) not belonging to the four haplogroups described by Horai is much greater than in contemporary indigenous populations. This permits us to suggest that, in addition to the postulated bottleneck effect during the migration from Asia to the Americas, the depopulation effect started by European colonization in the 16th century contributed to the reduction in genetic variability of Amerindians.
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Abstract
Selective distal splenorenal shunt was successfully performed in 20 patients from October 1974 to August 1978. All of them had had gastrointestinal hemorrhage from gastroesophageal varices, diagnosed by barium swallow roentgenography or esophagogastroscopy. Only one patient underwent emergency surgery. Portal hypertension was due to hepatic schistosomiasis in 16 patients, and all underwent rectal biopsy and examination of stools to confirm the clinical diagnosis. A small group of patients had ascites, jaundice and hemorrhage. Hepatic encephalopathy has not been a problem, although the follow-up study is short.
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Weston MJ, Gazzard BG, Buxton BH, Winch J, Machado AL, Flax H, Williams R. Effects of haemoperfusion through charcoal or XAD-2 resin on an animal model of fulminant liver failure. Gut 1974; 15:482-6. [PMID: 4851751 PMCID: PMC1412998 DOI: 10.1136/gut.15.6.482] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In a group of dogs in whom fulminant liver failure had been induced, perfusion of blood through activated charcoal resulted in a significantly longer survival than that of a similar group of dogs whose blood was not so treated. An otherwise progressive rise in blood ammonia concentration was halted in the treatment group. In another group of dogs with fulminant liver failure perfusion of blood through the resin Amberlite XAD-2 was associated with a fall in the serum bilirubin concentration and complete clearance from the blood of (14)C-labelled sodium glycocholate. Survival in this group of animals was not significantly prolonged. This was due at least in part to the occurrence of haemorrhage due to thrombocytopenia. Platelets adhere to the resin but do not adhere to the same degree to charcoal coated with a thin layer of polymer.
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Abstract
Abstract
The author reports his experiences with a technique which is extremely helpful not only in distinguishing between intra- and extrahepatic cholestasis but also in establishing preoperatively the aetiology of the jaundice, in this way helping the surgeon to choose the best surgical procedure.
The technique employed, the criteria of selection of the patients, the complications, and the results obtained in 53 patients are described.
To date, 53 patients have undergone percutaneous transhepatic cholangiography, and a total of 56 examinations have been performed in the radiography department under local anaesthesia.
In 1 patient a severe bile leakage occurred with signs and symptoms of biliary peritonitis and peralytic lesions.
The biliary tree was outlined in 41 patients out of 47 (87.2 per cent) with obstructive jaundice. In 6 patients the method failed (12.8 per cent).
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do Val HR, Machado AL. [A respiratory system using atmospheric air]. Braz J Anesthesiol 1969; 17:494-500. [PMID: 5257854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Lombardo CR, Machado AL, Jude JR. A new technique for resection of the aortic arch. J Thorac Cardiovasc Surg 1965; 50:677-82. [PMID: 5843975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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